Containers for blood, physiological solutions (such as parenteral solution or blood cell washing solution), or the like, are commonly used in a large variety of medical procedures. Usually, it is absolutely crucial that the blood or physiological solutions be retained in sterile manner. For example, once a conventional blood bag has been entered, following collection of the blood, it can no longer be stored, but must be used immediately to avoid the risk of catastrophic infection. Any significant delay may provide opportunity for microorganisms which have entered the blood or solution to multiply.
However, it would be desirable to obtain entry to the sterile contents of a container, while avoiding the risk of contamination, so that a portion of the sterile contents could be removed, or a medicament or other material added, and the resulting contents stored further for a few more days or weeks as desired.
For example, in cell washing procedures with the Travenol ELUTRAMATIC cell washing system, it is necessary to repeatedly draw aliquots of sterile cell washing solution from containers. At the present time, a large number of separate, small solution containers, must be used to preserve sterility, although it would be clearly more convenient to utilize a large container of parenteral solution by making repeated entries to the container, to remove the desired aliquots of solution.
In another aspect, it would be desirable to be able to obtain entry to sterile blood in a container, in order to withdraw only a portion of a blood unit. For example, a small child may need blood, but does not need a whole unit of blood. Also, one may wish to add medicaments, nutrients, or processing solutions to the blood; or to obtain access to blood components after the blood has been centrifuged, or the like.
In a third aspect, it is desirable in the field of hyperalimentation fluids (that is, feeding of a patient by means of a parenteral route) to mix protein solutions and carbohydrate solutions for administration of te mixture to the patient. However, it has been found that these solutions are extremely susceptible to bacterial growth, and thus, under current techniques, cannot reliably be stored without the danger of a rapid increase in bacterial contamination.
In accordance with this invention, a process and apparatus is provided for obtaining sterile access to the contents of a container, with such reliable sterility of access that the remaining contents may be further stored for essentially the same length of time as if no entry had been made to the container at all.
As a result of this, for the first time it becomes possible to make multiple entries into blood and solution containers without compromising the sterility, and without shortening the useful life of the contents of the container.